Daily Express owner Richard Desmond, one of Britain's most controversial media barons, condemned the official inquiry into media standards on Thursday as "the worst thing" to happen to newspapers.

He made the comments in a confident appearance before the Leveson Inquiry, which was set up to look at the culture, practices and ethics of the media following the phone hacking scandal which closed the News of the World tabloid.

"You know, this inquiry is probably the worst thing that's ever happened to newspapers in my lifetime, because it means -- you know, it's very hard at the moment in Britain in business, you know, it's very, very hard," Desmond said.

"People are looking at every single penny they're spending, and if they believe that newspapers are basically dishonest, hacking, low lifes, I suppose is the word, then they're not going to buy newspapers.

"And the last few months, the sales of newspapers have never been so bad."

Desmond, who owns a media empire that includes celebrity magazine OK!, Channel 5 television and several adult channels, said he was not blaming the inquiry itself but the hacking that sparked it, "which should have been nailed on the head years ago, and not left to go on for so many years".

"Hacking is illegal. Why are these people still walking the streets?" he asked, in reference to the fact that only two people have been jailed for hacking, despite signs that it was widespread at the News of the World.